278 SILTJRID^E. 



serrated, a little more than half length of fin. Ventral equally distant 

 from end of snout and from root of caudal. Caudal rounded. Dark 

 brown, almost black, above, pinkish white beneath. 



Described from a single specimen, 500 millim. long ; the species said 

 to grow to 1290 millim. In a young specimen, 90 millim. long, the 

 head is less depressed and the eyes are proportionally larger. 



Lake Tanganyika. 



1. Type. Mpala. Dr. W. A. Cunnington (C). 



2. Yg. Mbete. 



8. PLOTOSUS. 

 Lacep. Hist. Poiss. v. p. 129 (1803) ; Gunth. Cat. Fish. v. p. 23 (1864) ; Vaill. 



Bull. Mus. Paris, 1903, p. 119. 

 Platystacas, part., Bloch, Ausl. Fische, viii. p. 52 (1793). 



Body elongate, compressed, tapering to a point behind. A short 

 dorsal fin in front, with a pungent spine ; a second long dorsal and 

 a long anal, united with the caudal. Pectoral fin with the outer ray 

 spinoiis; ventral fin with 12 to 14 rays. Head feebly depressed; four 

 pairs of barbels — one nasal, one maxillary, two mandibulars. Eye with 

 free orbital margin. Jaws with a band of obtusely conical teeth ; 

 a group of large granular teeth on the vomer. Gill-membranes free 

 from the isthmus, deeply notched in the middle. A dendritic post-anal 

 apparatus. Air-bladder moderately large, free. 



Vertebrae 46-81 (16-19 + 30-62). Brachiostegal rays 11 to 13. 



Coasts of the Indian and Western Pacific Oceans, sometimes entering 

 fresh waters. One species has been found in fresh waters in East Africa. 



1. PLOTOSUS ANGUILLARIS. 



Silurus, sp. d, Forsk. Descr. Aniin. p. xvi (1775). 



Platystacas anguillaris, Bloch, Ausl. Fische, viii. p. 60, pi. ccclxxiii. fig. 1 (1793). 



Plotosus anguillaris, Lacep. Hist. Poiss. v. p. 129 (1803) ; Ptiipp. N. Wirbelth. 



Abyss., Fische, p. 76 (1835) ; Cantor, Cat. Mai. Fish. p. 264 (1850) ; Peters, 



Arch. f. Nat. 1835, p. 267; Gunth. Cat. Fish. v. p. 24 (1864); Sauv. Hist. 



Madag., Poiss. p. 477, pi. xlvii.A. fig. 1 (1891); Pfeff. Thierw. 0.-A£r., 



Fische, p. 29, fig. (1896). 

 Plotosus ihapor, Less. Voy. Coquille, Zool. ii. p. 132, pi. xxxi. fig. 3 (1830). 

 Plotosus margiriatus, Bennett, Life of Raffles, p. 691 (1830). 

 Plotosus Unealus, Cuv. & Val. Hist. Poiss. xv. p. 412 (1840) ; Schleg. Faun. 



Japon., Poiss. p. 228, pi. civ. fig. 3 (1846). 



